If we choose to live near convergent plate boundaries, we can build buildings that can resist earthquakes, and we can evacuate areas around volcanoes when they threaten to erupt. Yes, convergent boundaries are dangerous places to live, but with preparation and watchfulness, the danger can be lessened somewhat.
Nitrification, as stated above, is formally a two-step process; in the first step ammonia is oxidized to nitrite, and in the second step nitrite is oxidized to nitrate. Different microbes are responsible for each step in the marine environment.
This means that NH4+-N does not move downward in soils. Nitrogen in the NH4+-N form that is not taken up by plants is subject to other changes in the soil system. Nitrification is the conversion of NH4+-N to NO3--N . Nitrification is a biological process and proceeds rapidly in warm, moist, well-aerated soils.